When TTeeGrid.Data is a descendant of TDataSet, when you press enter in a cell after changing its value, no cell remains focused, although TTeeGrid.Editing.EnterKey: = NextCell,
When TTeeGrid.Data is not a TDataSet undoing behavior is correct (you can verify it in your demo TeeGrid_Custom_Sorting.dpr or C:\Program Files (x86)\Steema Software\Steema TeeGrid for VCL & FMX Registered version-1.05\demos\FireMonkey\Cell Editors\TeeGrid_FMX_Cell_Editors.dproj)